More than 150 deputies in the Iranian parliament have sent an open letter to the head of the judiciary, demanding an end to what they call an illegal and unwarranted arrest of liberal and reformist figures.

The protest follows the recent detention of more than 40 people associated with the banned liberal opposition group, Freedom Movement.

The judiciary is independent of the president's reformist government

The judiciary has said that those arrested were plotting to overthrow the Islamic regime.

Human rights organisations abroad have also strongly condemned the arrests. One group, Human Rights Watch, termed the arrests a creeping coup against the reformists.

Secret location

The letter, which was signed by well over half of the reformist-dominated parliament, was read out on the floor of the chamber.

A new reformist paper hits the streets - others have been shut down

It complained that many of the detainees were being held at a secret location and denied visits by their families or by lawyers.

But the MPs demanded to know why the intelligence ministry, which is supposed to be in charge of such issues, had been by-passed.

The intelligence minister appeared in parliament earlier this week. He said he had no information to suggest the detainees were involved in any such plots.

The judiciary, which is independent both of parliament and of President Mohammad Khatami's reformist government, had dismissed earlier criticism.

Condemnation

It said those who voiced it did not have access to incriminating evidence and confessions.

But the reformists are convinced that the intensifying wave of arrests and recent closures of newspapers are all part of a right-wing campaign to foil the reformist movement ahead of presidential elections in June.

The arrests have prompted similar accusations and condemnation from international human rights groups.

Human Rights Watch, said the judicial campaign was beginning to look like a coup aimed at denying the reformists their electoral success.

They have won both the presidency and parliament with huge public endorsement.

But popularity has not led to power, as hard-line conservatives maintain their grip on many key institutions.

President Khatami has not yet announced whether he intends to stand again in June.

His supporters believe the escalated campaign of arrests is aimed at dissuading and weakening him.